package com.sinopec.smcc.middle;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

/**
 * Z字形变换
 * @author pcitc
 *
 */
public class convert {
	 
	/*public static String convert(String s, int numRows) {

	        if (numRows == 1) return s;

	        List<StringBuilder> rows = new ArrayList<>();
	        for (int i = 0; i < Math.min(numRows, s.length()); i++)
	            rows.add(new StringBuilder());

	        int curRow = 0;
	        boolean goingDown = false;

	        for (char c : s.toCharArray()) {
	            rows.get(curRow).append(c);
	            if (curRow == 0 || curRow == numRows - 1) goingDown = !goingDown;
	            curRow += goingDown ? 1 : -1;
	        }

	        StringBuilder ret = new StringBuilder();
	        for (StringBuilder row : rows) ret.append(row);
	        return ret.toString();
	    }*/
	public static String convert(String s, int numRows) {

        if (numRows == 1) return s;

        StringBuilder ret = new StringBuilder();
        int n = s.length();
        int cycleLen = 2 * numRows - 2;

        for (int i = 0; i < numRows; i++) {
            for (int j = 0; j + i < n; j += cycleLen) {
                ret.append(s.charAt(j + i));
                if (i != 0 && i != numRows - 1 && j + cycleLen - i < n)
                    ret.append(s.charAt(j + cycleLen - i));
            }
        }
        return ret.toString();
    }
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		Scanner line = new Scanner(System.in);
		System.out.println(convert(sc.nextLine(),line.nextInt()));
	}
}
